• Energy Research

Comprehending the decomposition process is crucial for our understanding of the mechanisms of carbon (C) sequestration in soils. The decomposition of plant biomass has been extensively studied. It revealed that extrinsic biomass properties that restrict its access to decomposers influence decomposition more than intrinsic ones that are only related to its chemical structure. Fungal biomass has been much less investigated, even though it contributes to a large extent to soil organic matter, and is characterized by specific biochemical properties. In this study, we investigated the extent to which decomposition of heathland fungal biomass was affected by its hydrophobicity (extrinsic property) and melanin content (intrinsic property). We hypothesized that, as for plant biomass, hydrophobicity would have a greater impact on decomposition than melanin content. Mineralization was determined as the mineralization of soil organic carbon (SOC) into CO2 by headspace GC/MS after inoculation by a heathland soil microbial community. Results show that decomposition was not affected by hydrophobicity, but was negatively correlated with melanin content. We argue that it may indicate that either melanin content is both an intrinsic and extrinsic property, or that some soil decomposers evolved the ability to use surfactants to access to hydrophobic biomass. In the latter case, biomass hydrophobicity should not be considered as a crucial extrinsic factor. We also explored the ecology of decomposition, melanin content, and hydrophobicity, among heathland soil fungal guilds. Ascomycete black yeasts had the highest melanin content, and hyaline Basidiomycete yeasts the lowest. Hydrophobicity was an all-or-nothing trait, with most isolates being hydrophobic.

Perovskite materials have gathered increased interest over the last decade. Their rapidly rising efficiency, coupled with the compatibility with solution processing and thin film technology has put perovskite solar cells (PSC) on the spotlight of photovoltaic research. On top of that, band gap tunability via composition changes makes them a perfect candidate for tandem applications, allowing for further harvest of the solar irradiation spectrum and improved power conversion efficiency (PCE). In order to convert all these advantages into large scale production and have increased dissemination in the energy generation market, perovskite fabrication must be adapted and optimized with the use of high throughput, continuous processes, such as ultrasonic spray coating (USSC). In this paper we investigate the ultrasonically spray coated perovskite layers for photovoltaic applications, with particular focus on the quenching-assisted crystallization step. Different quenching techniques are introduced to the process and compared in terms of final layer morphology and cell performance. Finally, gas quenching is used with the large-scale-compatible deposition and allows the production of perovskite solar cells with PCE >15%.

The incrementally rising efficiency of perovskite-basedphotovoltaicdevices has established technology as a hot topic in past years. Transitioningthis class of materials from laboratorial to commercial applicationis key to the future of clean energy generation. In the interest ofthis transition, scalable fabrication and reproducibility are challengesto be overcome. Additionally, being a highly dynamic field with fast-pacedinnovation, perovskite research lacks in structured comprehensivestudies focusing on the processing parameters, especially when comparedto commercial technologies, such as silicon-based devices. This studyproposes a design of experiments (DoE) approach to analyze and optimizethe fabrication of perovskite thin films by ultrasonic spray coating,a scalable technique. The investigation of deposition parameters onefactor at a time (OFAT) and the more in-depth full factorial analysisof three key input variables allowed the assessment of the impactlevel of each factor on the quality and performance of the obtainedfilms of the fabricated photovoltaic devices. Furthermore, the fullfactorial analysis reveals the presence of interactions between factors.The study revealed that a shorter distance between the air gun andthe sample (2 cm) coupled with high gas pressure (7.6 bar) duringthe quenching step were the most influential parameters for the productionof high-quality films, leading to an average efficiency of 14.8%. This study was supported by the Special Research Fund (BOF) of Hasselt University, BOF number: BOF19OWB17. This project has also received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 850937. S.H. and P.V. acknowledge financial support by the Flanders Research Foundation (FWO), strategic basic research doctoral grants 1S31922N and 1S99121N, respectively

For almost sixty years, solar energy for space applications has relied on inorganic photovoltaics, evolving from solar cells made of single crystalline silicon to triple junctions based on germanium and III-V alloys. The class of organic-based photovoltaics, which ranges from all-organic to hybrid perovskites, has the potential of becoming a disruptive technology in space applications, thanks to the unique combination of appealing intrinsic properties (e.g. record high specific power, tunable absorption window) and processing possibilities. Here, we report on the launch of the stratospheric mission OSCAR, which demonstrated for the first time organic-based solar cell operation in extra-terrestrial conditions. This successful maiden flight for organic-based photovoltaics opens a new paradigm for solar electricity in space, from satellites to orbital and planetary space stations.